Cation complexing of crown ethers using fluorescence spectroscopy, part II

The complex formations of benzo[12]crown-4, benzo[15]crown-5 and benzo[18]c rown-6 with perchlorate salts of Mg2+, Li+ and Na+ were investigated using the steady state fluorescence emission spectroscopy in acetonitrile. The co mplexation enhanced quenched fluorescence spectra, (CEQFS) exhibited the io n complexation role of the macrocyclic ethers and equilibrium constant, K-e of 1:1 stoichiometry were estimated. The K, were found in the order of Mg > Na+ > Li+ for benzo[15]crown-5 whilst Na+ > Mg+ > Li+ order was found wi th benzo[12]crown-4 at 298 K. (C) 2000 Elsevier Science B.V. All rights res erved.